This looks fine enough......
http://www.artofproblemsolving.com/Forum/viewtopic.php?f=296&t=305555
soumik, everyone iwll know that if he.she googles it
show the work also
then it will be fine
the post here sums it up well:
http://www.goiit.com/posts/show/1138578.htm
also read through
http://en.wikipedia.org/wiki/Gamma_function
This looks fine enough......
http://www.artofproblemsolving.com/Forum/viewtopic.php?f=296&t=305555